Документы

The seal is the only marine mammal in the Caspian Sea, feeding on tulkas and other small fish, and preyed upon by land animals. It is an endemic species for the Caspian Sea and is vulnerable on that point of view. During its life history the Caspian seal migrates from the frozen North Caspian waters in the winter to the South Caspian in the summer timer and back to the North to give birth to the pups on the ice. During these migration time the seals can be found everywhere in the sea.

Active conservation efforts will be required to assure the Caspian seal does not eliminate from the Earth. As a major mammal, anchoring one end of the food web, it also plays an important role in the biodiversity of the Caspian Sea and is a remarkable indicator of the Caspian ecosystems health.

Toxicity tests are commonly used as a tool to determine the standards of water quality for chemicals and to discover appropriate organisms as bioindicators in toxicological studies, and also could be used as an essential tool for evaluation of the pollutant effects in aquatic ecosystems. The aim of the present study was to evaluate the sensitivity of two Caspian fish species, Caspian trout as an endangered species and Caspian Kutum using the static acute toxicity in response to nonylphenol, which is widely discharged into the Caspian Sea environment.

In addition, Caspian trout was approximately 6 times more sensitive than Caspian Kutum. Nonylphenol was reflected to be "highly toxic" to Caspian trout and "moderately toxic" to Caspian Kutum. The results could be considered in preparing plans for conservation and restocking management of Caspian Kutum and the endangered Caspian trout.